美国CHEMetrics K-4520型总硬度滴定测试盒
用于测试水中总硬度含量。例如：锅炉水。
规格参数：
| 产品类型 | Hardness (total) — Titrets® Titration Cells |
| 产品型号 | K-4520 |
| 测试范围 | 20-200 ppm 以CaCO3计 |
| 测试目盛 | 20, 22, 24, 26, 28, 30, 32, 36, 40, 50, 60, 70, 80, 100, 140, 200 ppm |
| 检测下限 | 20 ppm |
| 测试方法 | EGTA（总） |
| 测试次数 | 30次/盒 |
| 标准配置 | 30支安瓿瓶组件、1个Titrettor™工具、1个25mL样品杯、1份说明书 |
| 产品价格 | 咨询上海益朗仪器有限公司 |
Titrets®是美国CHEMetrics的专利（专利号：4,332,769）。
美国CHEMetrics 硬度测试盒
Visual Kits
| 测试范围 | MDL | 测试方法 | 测试盒货号 |
| 50-500 ppm 以CaCO3计 | 50 ppm | EGTA（钙） | K-1705 |
| 2-20 ppm 以CaCO3计 | 2.0 ppm | EGTA（总） | K-4502 |
| 20-200 ppm 以CaCO3计 | 20 ppm | EGTA（总） | K-4520 |
| 100-1000 ppm 以CaCO3计 | 100 ppm | EGTA（总） | K-4585 |
Methods
Hardness is a measure of the mineral content of water. Calcium and magnesium are the most common minerals that contribute to hardness. Hard water causes scaling in boilers and other industrial equipment, and diminishes the effectiveness of soaps and detergents.
The EGTA Method (calcium)
Reference: West, T. S., DSC, Ph.D., Complexometry with EDTA and Related Reagents, 3rd. ed., pp. 46, 164 (1969).The EGTA method is specific for calcium hardness. The EGTA titrant in alkaline solution is employed with a zincon indicator. Results are expressed as ppm (mg/L) CaCO3.
Shelf-life: eight months. Although the reagent itself is stable, the end point indicator has a limited shelf-life. We recommend stocking quantities that will be used within seven months.
The EDTA Method (total)
References: APHA Standard Methods, 23rd ed., Method 2340 C- 1997. USEPA Methods for Chemical Analysis of Water and Wastes, Method 130.2 (1983).The total hardness method is applicable to drinking, surface, boiler, and brine waters.
The EDTA titrant is employed in alkaline solution with a calmagite indicator. This method determines the combined calcium and magnesium concentration of a sample. If no magnesium is present, the end point of the titration normally appears sluggish. Results are expressed as ppm (mg/L) CaCO3.